Modification of cellulosic textiles with bis(dimethyloldihydroxyethyleneurea) p-dioxane



United States Patent 1 Claim. (Cl. 8-116.3)

This application is a division of application Ser. No. 432,022 filed Feb. 11, 1965, now Patent Number 3,- 383,390.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the .United States of America.

This invention relates to the preparation of non-hygroscopic N-methylol derivatives. More specifically, this invention relates to the preparation of N-methylol derivatives which are stable to the loss of formaldehyde either in the solid state or in aqueous solution. This type of chemical reagent should find increasing commercial acceptance in the art of textile wash-and-wear applications since there is no liberation of formaldehyde upon handling or storage.

The main object of this invention is to stabilize certain N-methylol compounds by reacting them with p-dioxane and isolating the solid product obtained.

Another object of this invention is to apply the compounds obtained to cellulosic textile materials either in the presence or in the absence of an inorganic salt catalyst to impart wash-and-wear properties to the said cellulosic materials.

Other objects of the invention will become evident in the description of the investigative work which yielded the unexpected results presented in this specification.

To those skilled in this art, it is well known that urea derivatives react with formaldehyde to yield compounds which contain N-methylol (hydroxymethyl) groups. These materials react readily with cellulosic textiles in the presence of acidic catalysts to impart desirable washand-wear properties to the finished fabric or garment. Prior to our invention the compounds used commercially to impart these desirable properties to cellulosics have not generally been isolated as solids. These have been available commercially only as aqueous solutions, and the N- methylol compounds have been prepared in situ by adding stoichiometric quantities of aqueous solutions of formaldehyde, usually as Formalin, to aqueous solutions of the urea derivative. An acid-type catalyst is also sometimes added to the resulting commercial solution.

The commercial solutions, generally, lose formaldehyde by decomposition of the dissolved compounds. Indeed, those N-methylol derivatives such as dimethylolethyleneurea (DMEU) and dimethyloldihydroxyethyleneurea IDMDHEU) illustrated below 3,414,369 Patented Dec. 3, 1968 lose formaldehyde even in the solid state due to their hygroscopic nature when exposed to the atmosphere. Such difiiculties in the handling of these materials in their commercial application to cellulosic textiles can be eliminated by the use of stable N-methylol compounds which are our invention. The preparation of these compounds is taught in the specification of this invention.

Generally, to prepare the stable derivatives, which are our invention, a compound of the following type is synthesized.

The compound, in which adjacent hydroxyl groups are located on a ring which has methylol groups attached to nitrogen atoms which are adjacent to a carbonyl group, is synthesized by reacting glyoxal, urea, and Formalin in aqueous solution having a final pH of about from 7 to 8. The excess water is removed prior to reaction with pdioxane. For the product of this reaction we here suggest the chemical name bis(dimethyloldihydroxyethyleneurea) p-dioxane, which we abbreviate as (DMDHEU)2ZDX.

The equation representing the formation of our product may be written as follows:

This chemical compound, which is part of our invention, is a white powdery solid substance which melts at 111.5 to 116.5 C. It has been solubilized in water and in hot methanol, and it is probably soluble in many common organic solvents and mixtures of solvents used in commercial applications.

Chemical analyses of the product, which was isolated from the mixture in the reaction flask, indicate that the compound which is part of our invention contains one mole of p-dioxane for every two moles of the N- methylol derivative, and a theoretical configuration of the product, (DM:DHEU) --Dx is this:

Bis (dimethyloldihydroxyethyleneurea) p-dioxane Compounds which contain a ring and methylol groups but which do not have adjacent hydroxyl groups on the ring, such as DMEU, or compounds which do not have N-methylol groups but blocked ring hydroxyl groups,

such as dimethoxyethyleneurea (DMxEU) having the structure below DMXEU H H T? HO OH OH OH DHEU does give a precipitate with p-dioxane. This indicates that ring hydroxyl groups and not -N-rnethylol hydroxyl groups are necessary in stabilizing such N-methylol compounds to atmospheric moisture and loss of formaldehyde by reaction with p-di0xane.

The specific preparation of the stabilized compound is described in Example 1, below, and Example 2 describes the application of the (DMDH'EUh-Dx to a cotton fabric. The stabilized compound may be applied to cellulosic textile materials from aqueous solutions with or without the assistance of a dissolved inorganic metal salt catalyst.

The impregnation of the cellulosic material is generally carried out in this manner. The material is immersed in an aqueous solution of the stabilized N- methylol compound of a molar concentration about from 0.22 to 0.50 without catalyst, imparting to the material wash-and-wear properties. However, if time is of essence, or if a more wrinkle resistant product is sought, the same concentrations of the N-methylol compound are used with an added catalyst selected from the following: zinc chloride, zinc nitrate hexahydrate, magnesium chloride hexahydrate, or magnesium nitrate heaxhydrate. One of these inorganic metal salt catalysts is employed in the same solution at a concentration of about 0.03 mole per liter of solution.

Once the material has been impregnated with the compound which is our invention, it must be dried at a temperature about from as low as room temperature (about 25 C.) to about 60 C. for about from 7 to 60 minutes, the longer periods of time generally employed with the lower temperatures. The dry impregnated material is then submitted to a cure at about from 120 to 160 C. for about from 3 to 10 minutes, again the longer periods of time being employed with the lower temperatures.

The range of curing time indicated above reflects the situation when an acid catalyst is not present in the impregnating solution. For the process of this invention, it is not necessary to add a catalyst for the purpose of Obtaining wrinkle resistant properties on the textile. However, as noted above, the use of a catalyst will improve wrinkle recovery properties and will reduce to some degree the time required for curing.

The materials to which the stabilized N-methylol compound of our invention can be applied from aqueous solution include cotton, rayon, ramie, jute, flax, and the like, and in the case of cotton we have specifically applied our invention to the textile in the form of woven fabrics with satisfactory results. Those skilled in the art can readily visualize the extension of this application to other forms of textiles in the realm of cellulosic materials.

The following examples are presented to illustrate the invention, and since procedure and conditions can be varied by those skilled in the art, the examples are not set forth to establish any particular limits. The preparation of an N-methylol compound stabilized by reacting same with p-dioxane is described. Also, the application of the compound of our invention to cellulosic textiles is illustrated by applying the same with and without an inorganic metal salt catalyst to cotton.

The treated cotton fabrics were submitted to selected standard tests as well as the other tests indicated here. Breaking strength determinations were done by the ASTM Method D39-40; dry wrinkle recovery determinations were done by the ASTM Method D1295-60T; and wet wrinkle recovery determintions were done by the Lawrence and Phillips method described in American Dyestuff Reporter, volume 45, P548550, 561 (1956). Nitrogen values were obtained by the Kjeldahl Method; metal analyses were done by ethylenediaminetetraacetic acid titration; and formaldehyde values were done by the chromotropic acid method. The carbon, hydrogen, and nitrogen values for the (DMDHBU)2DX of Example l were obtained by using standard microanalytical procedures.

Example 1 A non-hygroscopic N-methylol derivative was prepared as follows: To 197 parts of dihydroxyethyleneurea (DHEU), which was prepared by modification of a procedure in British Patent 717,287, was added one part of calcium hydroxide. To this mixture was added 276 parts of a 36.3% formaldehyde solution with continuous automatic stirring for four hours. To DHEU was dissolved after the first hour of stirring, accompanied by a rise in temperature. Crushed Dry Ice was then introduced into the solution until the pH was adjusted to 7. The viscous solution was separated from the precipitated calcium carbonate by filtration, and was then placed in a vacuum desiccator. The liquid was kept in vacuo over P 0 for 9 days to remove excess water.

When p-dioxane, at room temperature, was added to the viscous liquid, a white solid, which is the product of our invention, was immediately precipitated, and heat was liberated. The solid was filtered, washed with pdioxane, at room temperature, and again filtered. It was then pulverized in a mortar, recrystallized from hot methanol, filtered, washed 3 times in methanol, and dried in vacuo over sodium hydroxide pellets.

A fraction of the product was taken and further desiccated over P 0 under pump vacuum for a few days. This product, which is our invention, was not hygroscopic, and was observed and recorded as being free of formaldehyde odor. The melting point of the product which is our invention is 115.5116.5 (corr.).

Analysis.Calculated for C H N O carbon, 37.83; hydrogen, 6.35; nitrogen, 12.61. Found: carbon, 37.28;

hydrogen, 6.44; nitrogen, 12.68.

Example 2 Eight samples of cotton printcloth (68 x 72 thread count) weighing about from 9 to 10 grams each were impregnated with the various bath solutions shown in Table 1. Each sample was wetted and passed twice through a laboratory wringer to obtain approximately wet weight pickup. Each sample was dried in a forced-air oven 7 minutes at about 60 C., and cured 3 minutes at about C. Each sample was then washed in an automatic Washer-dryer, with water containing a detergent (Triton X-IOO), tumble-dried, and allowed to equilibrate in the laboratory under normal conditions. The treated samples were then submitted to select evaluation, as described earlier in the specification, and the desired and notable properties together with the results of chemical analyses were recorded, and are shown in Table l.

TABLE 1 Properties of Cotton Printcloth Treated With Bis((liniethyloldihydroxyetllyleneuron)p(lioxun0, (DMD IIEU); [)x

Composition of Bath Solutions Ret. Br. Crease Recovery Angles,

Wt. Gain, Metal, N, HCHO, Btr. (W), degrees (DMDHE U) 2. Dx Catalyst Used 1 percent percent percent percent percent Molarity Dry Wet 2.1 2 0. 05 0. 47 0. 04 90 232 197 1.1 2 0. 04 0. 0. 92 200 187 2. 2 2 0. 04 0. 59 0. 49 95 221 190 4. 8 0. 08 1. 15 1. 89 02 300 202 3. 2 0.11 1. 21 1. 77 41 317 288 3. 9 0. 0s 1. 12 1. 57 309 268 4.1 0.08 1.08 1. 63 52 301 201 0.27 Z11(N03)2.6H9O- 3.4 0.29 1.19 2.75 49 298 304 Untreated Control 2 0. 06 0.03 198 178 1 0.03 molar concentration. 2 Magnesium.

We claim: 15 25 to C. for about from 7 to 60 minutes, the 1. A process for imparting wash-and-wear property longer time invervals being used with the lower to cellulosic textiles comprising temperatures, and

(a) wetting the cellulosic textile with an aqueous solu- (d) curing the dry impregnated textile at about from tion containing about from 0.22 to 0.50 mole per to C. for about from 3 to 10 minutes, the liter of solution of bis(dimethyloldihydroxyethyl- 20 longer time intervals being used with the lower eneurea)p-dioxane, temperatures.

(b) removing excess solution from the wetted cellulosic textile by passing the textile through squeeze rolls to obtain a wet pickup of about 90% by weight based I on the weight of the textile 25 NORMAN G. TORCHIN, Plzmary Exammer.

(c) drying the wet impregnated textile at about from J. CANNON, Assistant Examiner.

No references cited. 

1. A PROCESS FOR IMPARTING "WASH-AND-WEAR" PROPERTY TO CELLULOSIC TEXTILES COMPRISING (A) WETTING THE CELLULOSIC TEXTILE WITH AN AQUEOUS SOLUTION CONTAINING ABOUT FROM 0.22 TO 0.50 MOLE PER LITER OF SOLUTION OF BIS(DIMETHYLOLDIHYDROXYETHYLENEUREA) P-DIOXANE, (B) REMOVING EXCESS SOLUTION FROM THE WETTED CELLULOSIC TEXTILE BY PASSING THE TEXTILE THROUGH SQUEEZE ROLLS TO OBTAIN A WET PICKUP OF ABOUT 90% BY WEIGHT BASED ON THE WEIGHT OF THE TEXTILE, (C) DRYING THE WET IMPREGNATED TEXTILE AT ABOUT FROM 25* TO 60*C. FOR ABOUT FROM 7 TO 60 MINUTES, THE LONGER TIME INVERVALS BEING USED WITH THE LOWER TEMPERATURES, AND (D) CURING THE DRY IMPREGNATED TEXTILE AT ABOUT FROM 120* TO 160*C. FOR ABOUT FROM 3 TO 10 MINUTES, THE LONGER TIME INTERVALS BEING USED WITH THE LOWER TEMPERATURES. 